The manufacturing of the present day integrated circuits (IC) are primarily outsourced to external companies. Under this business model, the design of the IC is exposed to tampering and cloning by the third party manufacturing company, thereby breaching the Intellectual Property (IP) of the design. Additionally, IC cloning also siphons off the economic benefits of the product. Due to these external manufacturing companies being employed by adversaries, isolating the forged ICs from the authentic ICs is becoming an increasingly difficult task.
Traditionally, unique keys are generated by the ICs for important applications, such as IP security, counter-plagiarism, etc. These unique keys are stored on the on-chip, non-volatile, memory that is considered to be impervious to illegal access and duplication. However, it is known that adversaries can decode these unique keys through Reverse Engineering (RE). A duplicated IC chip having a unique key obtained through RE cannot be distinguished from the genuine IC chip.
In an effort to address the issue of reverse engineering of unique IC security keys, an auxiliary circuit, commonly known as a Physically Unclonable Function (PUF), is incorporated into the authentic chips during the manufacturing process. PUFs are designed to exploit the unique physical properties of the individual chip (e.g. process) to generate a unique identification key for the chip. PUFs are unclonable, because duplication of the IC will not provide the same identification tag as the original IC, even if the ICs are functionally identical. PUFs operate on the foundation of a challenge-response protocol, which functions of the basis of uniqueness of the complex and variable nature of the physical process used to manufacture the IC.
PUFs fall under two basic categories: electronic and non-electronic. Electronic PUFs are based upon electronic properties that determine the challenge-response protocols, such as gate delay, threshold voltage switching times, etc. Electronic PUFs known in the art include Arbiter PUFs, Ring-Oscillator PUFs, SRAM PUFs and nano-electronic PUFs. The non-electronic PUFs use non-electrical challenge-response mechanisms for their operation. Non-electronic PUFs known in the art include optical PUFs, magnetic PUFs and acoustical PUFs. While the PUFs known in the art have been effective as security primitives to address hardware security issues, improvements are needed in the field of the invention to improve the robustness of the PUF devices, to decrease the area requirements and to reduce the power requirements of the PUF devices.
Accordingly, what is needed in the art is a system and method for user authentication which overcomes the deficiencies of the authentication systems and methods currently known in the art.